Techniques for achieving multiple transistor fin dimensions on a single die

ABSTRACT

Techniques are disclosed for achieving multiple fin dimensions on a single die or semiconductor substrate. In some cases, multiple fin dimensions are achieved by lithographically defining (e.g., hardmasking and patterning) areas to be trimmed using a trim etch process, leaving the remainder of the die unaffected. In some such cases, the trim etch is performed on only the channel regions of the fins, when such channel regions are re-exposed during a replacement gate process. The trim etch may narrow the width of the fins being trimmed (or just the channel region of such fins) by 2-6 nm, for example. Alternatively, or in addition, the trim may reduce the height of the fins. The techniques can include any number of patterning and trimming processes to enable a variety of fin dimensions and/or fin channel dimensions on a given die, which may be useful for integrated circuit and system-on-chip (SOC) applications.

BACKGROUND

Integrated circuit (IC) design, especially highly integratedsystem-on-chip (SOC) devices, involve a number of non-trivial issues,and transistor structures have faced particular complications, such asthose with respect to achieving devices with low-power dissipationside-by-side with high performance devices. Finned transistorconfigurations include a transistor built around a thin strip ofsemiconductor materials (generally referred to as the fin). Thetransistor includes the standard field effect transistor (FET) nodes,including a gate, a gate dielectric, a source region, and a drainregion. The conductive channel of the device effectively resides on theouter sides of the fin, beneath the gate dielectric. Specifically,current runs along/within both sidewalls of the fin (sides substantiallyperpendicular to the substrate surface) as well as along the top of thefin (side substantially parallel to the substrate surface). Because theconductive channel of such configurations essentially resides along thethree different outer, planar regions of the fin, such configurationshave been termed as finFET and tri-gate transistors. Other types offinned configurations can also be used, such as so-called double-gatefinFETs, in which the conductive channel principally resides only alongthe two sidewalls of the fin (and not along the top of the fin, forexample).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a method of forming an integrated circuit structureincluding multiple fin channel dimensions, in accordance with one ormore embodiments of the present disclosure.

FIG. 2 illustrates a perspective view of a semiconductor substrateincluding fins after a trench etch was performed to form the fins in thesubstrate, in accordance with an embodiment.

FIG. 3 illustrates a perspective view of the structure of FIG. 2 afterdepositing oxide material in the trenches and etching the trench oxidematerial to recess it below the level of the fins, in accordance with anembodiment

FIG. 4 illustrates a perspective view of the structure of FIG. 3including a dummy gate after forming the same on the fins, in accordancewith an embodiment

FIG. 5 illustrates a perspective view of the structure of FIG. 4including an insulator layer after depositing the same and polishing theinsulator layer to the top of the dummy gate, in accordance with anembodiment.

FIG. 6 illustrates a perspective view of the structure of FIG. 5(including an additional area being processed on the substrate,including fins from the additional area) after lithographically definingan area to be opened, in accordance with an embodiment.

FIG. 7A illustrates a perspective view of the structure of FIG. 6(excluding the additional area), after removing the dummy gate from theopened area to re-expose the channel region of the fins, in accordancewith an embodiment.

FIG. 7B illustrates a top planar view of the structure shown in FIG. 7A.

FIG. 7C illustrates a front cross-section view taken perpendicularly tothe fins and across the channel region of the structure shown in FIG.7A.

FIG. 8 continues from FIG. 7C and illustrates the resulting structureafter performing a trim etch to achieve trimmed fins in the channelregion, in accordance with an embodiment; FIGS. 7C and 8 may also beviewed as cross-sections taken at different locations of the same twofins post trim etch, in accordance with an embodiment.

FIG. 9 illustrates a perspective view of the structure of FIG. 8(including the additional area shown in FIG. 6) after additionalprocessing to form semiconductor devices, in accordance with one or moreembodiments.

FIG. 10 illustrates a computing system implemented with one or moreintegrated circuits configured in accordance with one or moreembodiments of the present disclosure.

DETAILED DESCRIPTION

Techniques are disclosed for achieving multiple fin dimensions on asingle die or semiconductor substrate, and even on a single continuousfin structure. In some cases, multiple fin dimensions are achieved bylithographically defining (e.g., hardmasking and patterning) areas to betrimmed using a trim etch process, leaving the remainder of the die (andother portions of a given fin structure) unaffected. In some such cases,the trim etch is performed on only the channel regions of a given set offins (one or more fins), when such channel regions are re-exposed duringa replacement gate process. The trim etch may include, for instance, lowion energy plasma processing or thermal processing, and it may narrowthe width of the fins being trimmed (or just the channel region of suchfins) by 2-6 nm, for example. Alternatively, or in addition, the trimmay reduce the height of the fins. The techniques can include any numberof patterning and trimming processes to enable a variety of findimensions and/or fin channel dimensions on a given die, which may beuseful for integrated circuit and system-on-chip (SOC) applications.Numerous configurations and variations will be apparent in light of thisdisclosure.

General Overview

As previously explained, there are a number of non-trivial issuesassociated with fabricating integrated circuits, and especiallysystem-on-chip (SOC) devices. For highly integrated SOC devices, therequirements for transistor performance are typically varied fordifferent portions of the chip. Logic areas may require very low leakagefor longer battery life, while power management areas may require highcurrent to actuate other systems in the package. These divergentrequirements are difficult to meet with a single transistor type. In thecontext of planar transistor device architecture, these issues arecommonly solved with different gate and channel dimensions. In thecontext of finned transistor device architecture (e.g., tri-gate orfinFET architectures), the channel dimensions are typically determinedby a spacer patterning technique that is limited to a single finheight/width dimension (and thereby a single height/width in the channelregion of the fin) on a given die.

Thus, and in accordance with one or more embodiments of the presentdisclosure, techniques are provided for achieving multiple findimensions on a single die, and even on a single continuous fin. In someembodiments, multiple fin dimensions are achieved by lithographicallydefining (e.g., hardmasking and patterning) areas to be trimmed and thenperforming a trim etch on only those areas, leaving the remainder of thefin and die (e.g., the areas that were not patterned) unaffected. Insome such embodiments, the trim etch is performed on only the channelregions of the lithographically defined area, when such channel regionsare re-exposed during a replacement gate process, for example. The trimetch may include, for instance, low ion energy plasma processing (e.g.,using Cl based chemistry) or thermal processing (e.g., using HCl orCl₂). The techniques can include any number of patterning and trimmingprocesses to enable a variety of fin dimensions and/or fin channeldimensions on a given die, which may be useful for integrated circuitand system-on-chip (SOC) applications.

As will be apparent in light of this disclosure, the fins being trimmedon a given die (e.g., a first set of one or more fins) may have aninitial/first width (W1) before trim etch greater than 10 nm (e.g., 15,20, or 30 nm). After trim etch, those fins being trimmed may have asecond width (W2) of 15 nm or below (e.g., 15, 10, or 7 nm). In someembodiments, only the channel region of the fins may be trimmed (e.g.,during a replacement gate process), resulting in the trimmed fins eachhaving a narrower channel region relative to the source/drain regions ofthe same fins. In some cases, the trim etch may cause a narrowing of thefin by 2-6 nm. In some embodiments, it may be desirable to reduce theheight of the fins as little as possible while performing the trim etchto narrow the width of the fins. For example, it may be desirable toensure trimmed fins have a trimmed height of 20 nm or more above thetrench oxide plane. Therefore, in some embodiments, it may be desirableto start off with a high initial fin height (e.g., greater than 25, 30,50, or 75 nm). In some embodiments, the width and/or height of trimmedfins may be reduced by a desired percentage, such as 10, 15, 20, or 25%,or some other suitable percentage based on the desired application.Reducing the fin width in the channel region can make it easier toelectronically invert the channel by application of gate bias and reducecarrier leakage when the gate is not biased. In the remaininguntrimmed/unaffected fins (e.g., a second set of fins), the fins mayhave a third width (W3), which may be equal to or substantially similarto W1.

Note that change in fin height in some circumstances may beunintentional or otherwise unavoidable and planned for accordingly. Forinstance, in some such cases, the change in fin height is effectively abyproduct of width trimming procedures. Yet in other embodiments,however, the fin height may be intentionally changed to provide aspecific fin height. In such embodiments, multiple fin heights can beachieved on a single die and/or multiple transistor finned channelheights can be achieved, for example. For instance, in a CMOSapplication it may be useful to provide multiple fin height values alongthe same fin, such as a first fin height of 30 nm for p-type transistorsand a second fin height of 20 nm for n-type transistors.

So, depending on the application and desired circuit performance, asingle die can have multiple transistor geometries. Some of thosetransistors may have a first fin width in the channel region whileothers of those transistors may have a second fin width in the channelregion, or a third fin width and so on. Likewise, some of thosetransistors may have a first fin height in the channel region whileothers of those transistors may have a second fin height in the channelregion, or a third fin height and so on. To this end, each transistordevice on that die can be configured as needed for a given application,and may have any suitable geometry (width/height combination). In someexample embodiments, the diverse transistor geometries are on the samefin, while in other embodiments a first transistor geometry is providedin a first location on the die and a second transistor geometry isprovided in a second location on the die, and so on. In still otherembodiments, a single die can be configured with different fin setshaving different transistor geometries as well as one or more singlefins having diverse transistor geometries.

Recall that any number of patterning and trimming processes can beperformed to enable a variety of fin dimensions or fin channeldimensions on a given die. For example, if a second sequence ofpatterning and trimming is performed, a third set of fins can beproduced having fin dimensions that may differ from the first two sets,and so on. Note that a set of fins as used herein includes one or morefins. After forming multiple sets of fins having differing dimensions(or at least differing dimensions among the channel region of the setsof fins), various semiconductor devices (e.g., transistors) can beformed on the fins, including finned metal-oxide-semiconductor (MOS)transistor devices (e.g., tri-gate or finFET devices). Such MOStransistor devices may include n-type MOS devices (n-MOS), and p-typeMOS devices (p-MOS), and complementary MOS devices (CMOS).

Upon analysis (e.g., scanning electron microscopy and/or compositionmapping), a structure configured in accordance with one embodiment willeffectively show multiple fin dimensions and/or multiple fin channeldimensions on a given die or even on a given single continuous fin. Insome embodiments, only the channel region of a set of fins may betrimmed and thus have a narrower width relative to the source/drainregions of the set of fins and relative to the channel region of anotherset of fins on the given die. For example, the techniques describedherein may create a first set of fins formed on and from a givensubstrate/die, where the first set of fins each have a first width (W1)in the source/drain regions and a second width (W2) in the channelregion, such that W2 is less than W1. Further, the given substrate/diemay have a second set of fins, where the second set of fins each have athird width (W3) in the source/drain regions and the channel region(e.g., having a consistent width in all three regions of the fin). Insuch an example case, W3 may be equal to or substantially similar to W1,since these regions would be unaffected by any trim etch performed, aswill be described herein. Therefore, the widths W1, W2, and W3 can beinspected and compared.

Further, in some cases, integrated circuits fabricated using thetechniques described herein (e.g., from a single substrate/die) canprovide an improvement over conventional structures with respect to, atleast, providing different transistor performance sections based on thelocation of the transistors on the given substrate/die. For example, anarea of the integrated circuit die may include a first set of finsformed at one location on the die and having channel dimensions suitablefor low leakage/longer battery life applications (e.g., logic areas),and a second set of fins formed at another location on the die andhaving channel dimensions suitable for high current applications (e.g.,power management areas). As will be further appreciated in light of thisdisclosure, such geometrically diverse transistor areas of the die mayalso be formed on the same continuous fin. Therefore, integratedcircuits including multiple fin dimensions or multiple fin channeldimensions as variously described herein may be useful forsystem-on-chip (SOC) applications, especially highly integrated SOCapplications. Numerous configurations and variations will be apparent inlight of this disclosure.

Methodology and Architecture

FIG. 1 shows a method 101 of forming an integrated circuit structureincluding multiple fin channel dimensions, in accordance with one ormore embodiments of the present disclosure. As will be apparent in lightof this disclosure, trimming/sculpting (e.g., using a trim etch asvariously described herein) to achieve different fin channel dimensionsis described herein in the context of a replacement gate process, suchas a replacement metal gate (RMG) process. However, in some embodiments,the trimming/sculpting may be performed before gate (or dummy gate)deposition, to trim each fin in both the source/drain regions and thechannel regions, as will be discussed in more detail below. FIGS. 2-9illustrate example structures that are formed as the process flow ormethod 101 of FIG. 1 is carried out, in accordance with someembodiments. Although method 101 of FIG. 1 and the structures shown inFIGS. 2-9 are depicted and described herein in the context of formingfinned transistor configurations (e.g., tri-gate or finFET) havingvarying channel dimensions, similar principles and techniques asvariously described herein may be used for other transistorconfigurations, including, for example, planar, dual-gate,gate-all-around (e.g., nanowire/nanoribbon), and other suitablesemiconductor devices and configurations, as will be apparent in lightof this disclosure.

FIG. 2 illustrates a perspective view of semiconductor substrate 200including fins 210 and 220 after trench etch 102 was performed to formfins 210 and 220 in substrate 200, in accordance with an embodiment. Insome cases, method 101 may include initially providing substrate 200such that trench etch 102 can be performed on the provided substrate200. Substrate 200 may include, be formed from, deposited with, or grownfrom silicon, polycrystalline silicon, or single crystal silicon, forexample. Substrate 200 may be formed using various other suitabletechnologies for forming a silicon base or substrate, such as a siliconsingle crystal wafer. Substrate 200 may be implemented, for example,with a bulk silicon, a silicon-on-insulator configuration (SOI), or withmulti-layered structures, including those substrates upon which fins areformed prior to a subsequent gate patterning process. In otherimplementations, substrate 200 may be formed using alternate materials,which may or may not be combined with silicon, such as germanium. In amore general sense, any material that may serve as a foundation uponwhich a semiconductor device may be built can be used in accordance withembodiments of the present disclosure. Substrate 200 may also beconsidered a die for the purposes of this disclosure.

With further reference to FIG. 2, and as previously described, fins 210and 220 were formed in substrate 200 after trench etch 102 wasperformed. Therefore, in this embodiment, fins 210 and 220 are formed onand from substrate 200. In other embodiments, fins 210 and 220 may beformed, grown, or produced by other suitable processes. For example, insome cases, fins 210 and 220 may be grown (e.g., epitaxially) fromtrenches formed in substrate 200. FIG. 2 also shows trench 215 formedbetween fins 210 and 220. Fins 210 and 220 can be formed using anysuitable techniques, as will be apparent in light of this disclosure.For example, in some cases, trench etch 102 may include patterning andetching a thickness of substrate 200 using a resist or hardmask to formfins 210 and 220. In some such cases, multiple resist or hardmask layersmay be used for the patterning materials. In some cases, trench etch 102may include using an O₂ or O₂/Ar plasma etch at pressures in the 10-100mTorr range, and at room temperature, for example.

As can be seen in FIG. 2, fins 210 and 220 are depicted as rectangularin shape for ease of description. However, the fins as variouslydescribed herein need not be so limited. For example, in otherembodiments, the fins formed during trench etch 102 may have a roundedtop, a triangular shape, or some other suitable fin shape as will beapparent in light of this disclosure. As will also be apparent in lightof this disclosure, fins 210 and 220 may be used for n-type MOS devices(n-MOS), p-type MOS devices (p-MOS), or a CMOS device (e.g., where fin210 will be an n-type MOS and fin 220 will be a p-type MOS), forexample. Also note that although only two fins 210 and 220 (and trench215 formed between) are shown for ease of description; however, it iscontemplated that any number of similar fins and trenches may be formedon substrate 200 (e.g., hundreds of fins, thousands of fins, millions offins, billions of fins, etc.) and benefit from the techniques describedherein.

FIG. 3 illustrates a perspective view of the structure of FIG. 2including shallow trench isolation (STI), provided by isolation regions202, after depositing 103 insulator material in the trenches and etchingthe insulator material to recess it below the level of fins 210 and 220,in accordance with an embodiment. Deposition 103 to form isolationregions 202 may include atomic layer deposition (ALD), chemical vapordeposition (CVD), spin-on deposition (SOD), high-density plasma (HDP),plasma enhanced chemical deposition (PECVD), and/or some other suitabletechnique. In cases where patterning hardmask was used to form fins 210and 220, the hardmask can be removed prior to depositing the trenchoxide material. In some cases, the insulator or oxide material may bepolished flat to the level of the top of fins 210 and 220, prior toetching the material to recess it below the level of fins 210 and 220.Isolation regions 202 may comprise, for example a dielectric, such assilicon dioxide (SiO₂). However, the isolation regions 202 may be anyinsulator, oxide, or inter-layer dielectric (ILD) material whichprovides the desired amount of electrical isolation for a given targetapplication or end-use, as will be apparent in light of this disclosure.

FIG. 4 illustrates a perspective view of the structure of FIG. 3including dummy gate 230 after forming 104 the same on fins 210 and 220,in accordance with an embodiment. As previously described, thetechniques disclosed herein for achieving multiple fin channeldimensions can be performed during the replacement gate process, whichmay also be known as a replacement metal gate (RMG) process. In thisembodiment, dummy gate 230 can first be deposited by depositing a dummygate dielectric/oxide and dummy gate electrode 232 (e.g., dummypolysilicon). The resulting structure can be patterned and spacermaterial 240 can be deposited and etched to form the structure shown inFIG. 4. Such depositions, patterning, and etching can be done using anysuitable techniques, as will be apparent in light of this disclosure.Note that dummy gate oxide is not shown, because it is under the dummyelectrode/polysilicon layer 232, in this example embodiment. Also notethat dummy gate 230 is indicated on top of spacer material 240 for easeof reference and that dummy gate 230 (which includes dummy gate oxideand dummy electrode/polysilicon layer 232) as referred to herein may ormay not include spacer material 240 when being discussed.

FIG. 5 illustrates a perspective view of the structure of FIG. 4including insulator layer 250 after depositing 105 the same andpolishing layer 250 to the top of dummy gate 230, in accordance with anembodiment. Insulator layer 250 may comprise any suitable fillermaterial, including a dielectric material, such as SiO₂, deposited byALD, CVD, SOD, HDP, PECVD, and/or some other suitable technique, as willbe apparent in light of this disclosure.

FIG. 6 illustrates a perspective view of the structure of FIG. 5(including an additional area being processed on die/substrate 200,including fins 310 and 320) after lithographically defining 106 an areato be opened, in accordance with an embodiment. In this exampleembodiment, lithographically defining 106 the area to be opened includesa hardmasking and patterning process, resulting in the hardmask 270pattern shown. Hardmask layer 270 can have any desired configuration andthickness, and in some instances, may be provided as a substantiallyconformal layer. Hardmask layer 270 can be formed, for example, usingchemical vapor deposition (CVD), a spin-on process, and/or any otherprocess suitable for providing a layer of hardmask material, as will beapparent in light of this disclosure. Also, in some embodiments,hardmask layer 270 can comprise, for example, a nitride, such as siliconnitride (Si₃N₄). However, hardmask layer 270 is not so limited inmaterial composition, and in a more general sense, hardmask layer 270may be any hardmask material having sufficient resilience for a giventarget application or end-use, as will be apparent in light of thisdisclosure.

After hardmask layer 270 has been formed, any suitable and/or custompatterning process can be utilized to pattern hardmask layer 270, asdesired. In some embodiments, hardmask layer 270 may be patterned toopen areas including dummy gates covering fins desired to be sculpted(as will be described below). As illustrated in the example embodimentshown in FIG. 6, hardmask layer 270 was patterned to open the areaincluding dummy gate 230 (including dummy gate oxide 232). However, notethat dummy gate 330 (including dummy gate oxide 332) covering thechannel region of fins 310 and 320 was not opened during the patterningprocess of lithographically defining 106 the area to be opened, as willbe discussed in more detail below. Any suitable area may be opened asdesired via patterning of the hardmask layer to gain access to one ormore dummy gates (each dummy gate covering the channel region of one ormore fins), to achieve multiple fin channel dimensions on a singlesubstrate/die 200, as will be apparent in light of this disclosure.

FIG. 7A illustrates a perspective view of the structure of FIG. 6(excluding the additional area shown in FIG. 6 that included fins 310and 320), after removing 107 dummy gate 230 to re-expose the channelregion 206 of fins 210 and 220 (or what may become the channel regiononce the device is fully fabricated), in accordance with an embodiment.Removing 107 dummy gate 230, may include removing any capping layer(e.g., formed by spacer material 240) on top of the dummy gate, and thenremoving dummy gate electrode/poly-Si 232 and dummy gate oxide. Suchremoval may be done using any suitable etch, polish, and/or cleanprocess, as will be apparent in light of this disclosure. Recall thatremoving 107 the dummy gate is only occurring for dummy gate 230 in thisexample embodiment (and not occurring for dummy gate 330 shown in FIG.6, for example), as a result of the hardmasking and patterning process106 performed to open the area containing dummy gate 230. FIG. 7Billustrates a top planar view of the structure shown in FIG. 7A. As canbe seen in this top planar view, channel region 206 of fins 210 and 220have been re-exposed. As can also be seen, and as will be discussed inmore detail below, fins 210 and 220 each have a first width W1.

FIG. 7C illustrates a front planar view of only the channel region 206of the structure shown in FIG. 7A. As can be seen in FIG. 7C, fins 210and 220 each have a first width W1 and first height H1. Although fins210 and 220 need not have the same initial width W1 and height H1, theyare the same in this embodiment for ease of description. Note that firstheight H1 as used herein is the distance from the top of isolationregion 202 to the top of the fins 210 and 220. Also note that the sourceand drain regions of fins 210 and 220 (or what may become the source anddrain regions once the device is fully fabricated) start out with thesame initial/first width W1 and height H1 as the channel region 206 offins 210 and 220. For example, as can be seen in FIGS. 7A-B, the initialfin width W1 and height H1 is the same in the source/drain regions as itis in the channel region 206. In some embodiments, and as will beapparent in light of this disclosure, the first width W1 may bedetermined by trench etch 102, which was performed to form fins 210 and220 in substrate 200.

FIG. 8 continues from FIG. 7C and illustrates the resulting structureafter performing trim etch 108 of the channel region 206 of fins 210 and220 to achieve sculpted/trimmed fins 212 and 222, respectively, inaccordance with an embodiment. In some embodiments, trim etch 108 may beperformed using and/or inside of an epitaxial deposition tool or anepitaxial reactor. In some embodiments, trim etch may include, forexample: 1) low ion energy plasma processing using chlorine (Cl) orfluorine (F) based chemistry or 2) thermal processing. In someembodiments, using Cl or F based chemistry may include using less than 5kW (or less than 1 kW) of radio frequency energy, such as for between 10and 40 seconds. In some embodiments, the low ion energy plasmaprocessing may use an epitaxial deposition tool and a Cl based chemistryto achieve trim etch 108. One such example includes using low energy Clcontaining plasma under the following conditions: 200 mT, 10 sccm Cl₂,100 sccm H₂, 300 sccm Ar, 50 W, ion energy 2 eV, 20 seconds. In someembodiments, the thermal processing may employ epitaxial reactor orwafer chamber processing to achieve trim etch 108. In some embodiments,the thermal processing may employ an epitaxial deposition reactor withCl₂ in the temperature range of 500-700 degrees C. or HCl in thetemperature range of 700-900 degrees C., such as for between 20 and 120seconds, for example. One such example includes thermal processing underthe following conditions: 750 degrees C., 100 sccm HCl, 10000 sccm H₂,20 T, 60 seconds. Any number of suitable etching processes may be usedfor trim etch 108 as will be apparent in light of this disclosure.

As can be seen in FIG. 8, trimmed fins 212 and 222 have each beensculpted/trimmed to second width W2 and second height H2, in thisexample embodiment. Recall that only the channel region 206 of fins 210and 220 were sculpted/trimmed, resulting in trimmed fins 212 and 222.The source/drain regions of fins 210 and 220 are unaffected by trim etch108 in this example embodiment, because they are covered by at leastinsulator layer 250 (e.g., as shown in FIGS. 7A-B). Note that thesource/drain regions as well as the channel region of fins (e.g., fins310 and 320 shown in FIG. 6) in unopened areas (e.g., areas left coveredby hardmask layer 270 during the previous hardmask and patterning 106)are also unaffected by trim etch 108. In some embodiments, W2 may beequal to or less than W1. In some embodiments, H2 may be equal to orless than H1. In some embodiments, W1 may be greater than 15 nm and W2may be 15 nm or less. In some embodiments, W1 may be between 1 nm and 15nm greater than W2. In some embodiments, W1 may be between 2 nm and 6 nmgreater than W2. In some embodiments, W1 may be greater than 10 nm(e.g., 15, 20, or 30 nm wide). In some embodiments, W2 may be 15 nm orless (e.g., 15, 10, or 7 nm wide). In some embodiments, W2 may be atleast 5 nm. In some embodiments, H2 may be at least 20 nm. In someembodiments, H1 may be no more than 5 nm greater than H2. In someembodiments, it may be desirable to ensure that H2 is at least 20 nmafter trim etch 108 is performed. Thus, in some embodiments, it may bedesirable to start with fins having a high initial height H1 (e.g., atleast 25, 30, 50, or 75 nm), to ensure a sufficient trimmed fin heightH2 is remaining after trim etch 108. Note that, in this exampleembodiment, trimmed portions 212 and 222 of fins 210 and 220 are aboveisolation regions 202, and that the fins maintained their original widthW1 in the portions next to or within isolation regions 202, as shown,for example, in FIG. 8.

Recall that although fins 210 and 220, as well as trimmed fin portions212 and 222, are depicted as rectangular in shape, the disclosure neednot be so limited. In some embodiments, where the fins have an irregularwidth from top to bottom, only a portion of the fins may be sculptedduring trim etch 107. For example, in cases where the initially formedfins are tapered (e.g., where the top is thinner than the base), it maybe desirable to primarily sculpt or only sculpt the bottom portion ofthe fin during trim etch 107. In such cases, the sculpting may beperformed to achieve a more consistent width for the entirety of thechannel portion of the fin. For example, trim etch 107 may be performedin such cases to shape the fins to be straight (rather than tapered). Inanother embodiment, the fin will have a saddle shape, such that theheight and width are greatest at the edges of the channel where the finmeets the spacer sidewall. In such embodiments, in the center of thechannel, the fin will be shorter and narrower. Other suitableconfigurations or variations for performing trim etch 107 will depend ona given application and will be apparent in light of this disclosure.

In a further embodiment, note that FIGS. 7C and 8 can also be viewed asrespective cross-sections at two different locations of the same twofins, after the trim etch has been completed. For instance, thecross-section taken in FIG. 7C at the 210/220 location of the finsdepicts a first fin height H1 and width W1, while the cross-sectiontaken in FIG. 8 at the 212/222 location of those fins depicts a secondfin height H2 and width W2. Any number of other mixed fin geometrieswill be apparent in light of this disclosure, whether on different finsets, the same fin, or a combination thereof.

Method 101 of FIG. 1 may continue with repeating 109 processes 106(lithographically defining area to be opened), 107 (removing dummygate(s) from open area to re-expose channel region of fins in the openarea), and 108 (performing a trim etch on the channel region of the finsin the open area) as desired, in accordance with one or more embodimentsof the present disclosure. Processes 106, 107, and 108 can be performedonce each, to achieve, for example, two sets of fins having differentfin channel widths (e.g., as will be discussed below with reference toFIG. 9). However, processes 106, 107, and 108 may be repeated 109 asmany times as desired to achieve a variety of fin channel dimensions ona given substrate/die and/or even at different locations along the samefin if so desired (e.g., CMOS device), as will be apparent in light ofthis disclosure. Note that when repeating lithographically defining 106the area to be opened, any suitable area on the substrate/die 200 may bechosen. Also note that when repeating trim etch 108, differentconditions may be used to sculpt the re-exposed fin channel regions asdesired, such as in a manner listed above or any other suitable manner.

Method 101 of FIG. 1 may optionally continue with forming 110 one ormore semiconductor devices as is conventionally done, in accordance withsome embodiments. For example, FIG. 9 illustrates a perspective view ofthe structure of FIG. 8 (including fin 310 from the additional area ondie/substrate 200 shown in FIG. 6), after additional processing to formsemiconductor devices (e.g., after completing the replacement gateprocess and performing source/drain contact trench etch), in accordancewith one or more embodiments of the present disclosure. In this exampleembodiment, two finned transistors (e.g., a tri-gate or finFET) havebeen formed. As can be seen in FIG. 9, fins 210 and 310 are shown forillustrative purposes, and fin 210 is trimmed 212 in the channel region206. As can also be seen, fin 210 maintained first width W1 in thesource/drain regions 208 and 209, and fin 310 has a consistent width(W3) throughout its source/drain regions 308 and 309 and its channelregion 306. In other words, the source/drain regions 208 and 209 of fin210 and the entirety of fin 310 were unaffected by trim etch 108, sincetrim etch 108 was performed when only the channel region 206 of fins 210and 220 were exposed. As a result, the adjacent resistance paths throughthe source/drain regions 208 and 209 of fin 210 (as well as any relatedtip regions and the contacts) may all be relatively lower (e.g.,compared to the resistance paths through source/drain regions 308 and309) due to the physically wider dimension of the fin in thesource/drain regions as compared to the trimmed portion 212 of fin 210in the channel region 206.

In some embodiments, the width W3 of fin 310 may be equal to orsubstantially similar (e.g., within 1 or 2 nm) to W1. In a more generalsense, W1 and W2 may represent the width in the source/drain regions andthe channel region, respectively of each fin in a first set of fins,where the first set of fins were selectively trimmed according to method101. W3 may represent the width in all regions (source/drain andchannel) of all remaining fins, which may constitute a second set offins. As previously described, the selective sculpting/trimming of anarea of fins may be repeated 109 as many times as desired. Therefore,any number of sets of fins (e.g., 3, 4, 5, . . . n sets) may be formedon a given substrate/die using the techniques described herein toachieve a variety of fin channel dimensions. In some embodiments, thechannel region of all of the sets of fins may be sculpted/trimmed tosome degree (relative to the source/drain regions of those fins).Therefore, in some embodiments, the fin channel width of all fins on agiven substrate/die may be less than the fin width in correspondingsource/drain regions. Note that, in this example embodiment,source/drain regions 208/209 and 308/309 are shown as a part of theoriginal fins 210 and 310, respectively formed on and from substrate200. However, the present disclosure need not be so limited. Forexample, in some embodiments, any and/or all source/drain regions may beremoved and replaced with another material, and therefore, some or allof the source/drain regions may have no portion of the original fins inthem. In other embodiments, any and/or all of the source/drain regionsof the fins may also undergo thinning, sculpting, reshaping, cladding,and/or other various suitable processes. Therefore, in some embodiments,the width of the fin portion in the source/drain regions may not beequivalent to the original fin width (e.g., width W1 shown in FIGS. 7Cand 8).

With further reference to FIG. 9, gate electrodes 262 and 362 weredeposited/formed to replace dummy gate electrodes 232 and 332,respectively, in this embodiment, and optional gate dielectric (notshown) may be formed directly under gate electrodes 262 and 362, asconventionally done. As can also be seen, spacers 240 and 340 are formedaround gates 260 and 360, respectively, and gates 260 and 360 also havehardmask 280 and 380 formed thereon (which may be removed to form ametal gate contact). Gate electrodes 262 and 362 and gate dielectric maybe formed using any suitable technique and from any suitable materials.For example, replacement gates 260 and 360 can be formed using any of awide variety of processes, including CVD, physical vapor deposition(PVD), a metal deposition process, and/or any combination thereof. Insome embodiments, gate electrodes 262 and 362 may comprise any of a widerange of materials, such as polysilicon or various suitable metals(e.g., aluminum (Al), tungsten (W), titanium (Ti), copper (Cu), or anyother suitable metal or alloy). Other suitable configurations,materials, and processes for forming a replacement gate or replacementmetal gate (RMG) will depend on a given application and will be apparentin light of this disclosure.

With further reference to FIG. 9, an etching process (e.g., any suitablewet or dry etching process) was performed to expose the source/drainregions 208, 209 and 308, 309 of fins 210 and 310, respectively, asshown. Method 101 to form an integrated circuit device may includeadditional or alternative processes as will be apparent in light of thisdisclosure. For example, the method may continue with source/drainprocessing and may include the deposition of source/drain metal contactsor contact layers. Such metallization of the source and drain contactscan be carried out using a silicidation process (generally, depositionof contact metal and subsequent annealing). For instance, silicidationwith nickel, aluminum, nickel-platinum or nickel-aluminum or otheralloys of nickel and aluminum, or titanium with or without germaniumpre-amorphization implants can be used to form a low resistancegermanide.

In some embodiments, the principles and techniques as variouslydescribed herein may be used to sculpt/trim the entirety of fins in anopened area, before gates (or dummy gates) are deposited. For example,this may include lithographically defining (e.g., hardmasking andpatterning) an area to be sculpted/trimmed and then performing a trimetch to sculpt/trim the fins in the area, before gates are deposited. Insuch embodiments, the dimensions of each fin from the sculpted/trimmedarea would be the same in both the source/drain regions and the channelregion. The processes for selectively sculpting/trimming an area of finscan be repeated as many times as desired to achieve a variety of findimensions on a given substrate/die.

As previously mentioned, method 101 and the structures shown in FIGS.2-9 are depicted and described herein in the context of finnedtransistor configurations (e.g., tri-gate or finFET) having varyingchannel dimensions, for ease of illustration. However, the principlesand techniques as variously described herein may be used for formingother semiconductor devices and transistor configurations on a singledie having multiple fin dimensions, including, for example, planar,dual-gate, gate-all-around (e.g., nanowire/nanoribbon), and othersuitable devices and configurations. Also recall that the structuresdescribed herein may be used for the formation of p-MOS, n-MOS, or CMOStransistor devices, depending upon the particular configuration.Numerous variations and configurations will be apparent in light of thisdisclosure.

Example System

FIG. 10 illustrates a computing system 1000 implemented with one or moreintegrated circuits configured in accordance with one or moreembodiments of the present disclosure. As can be seen, the computingsystem 1000 houses a motherboard 1002. The motherboard 1002 may includea number of components, including but not limited to a processor 1004and at least one communication chip 1006, each of which can bephysically and electrically coupled to the motherboard 1002, orotherwise integrated therein. As will be appreciated, the motherboard1002 may be, for example, any printed circuit board, whether a mainboard or a daughterboard mounted on a main board or the only board ofsystem 1000, etc.

Depending on its applications, computing system 1000 may include one ormore other components that may or may not be physically and electricallycoupled to the motherboard 1002. These other components may include, butare not limited to, volatile memory (e.g., DRAM), non-volatile memory(e.g., ROM), a graphics processor, a digital signal processor, a cryptoprocessor, a chipset, an antenna, a display, a touchscreen display, atouchscreen controller, a battery, an audio codec, a video codec, apower amplifier, a global positioning system (GPS) device, a compass, anaccelerometer, a gyroscope, a speaker, a camera, and a mass storagedevice (such as a hard disk drive, compact disk (CD), digital versatiledisk (DVD), and so forth). Any of the components included in computingsystem 1000 may include one or more integrated circuit structures asvariously described herein (e.g., including multiple fin dimensions,particularly in the channel region of the fins). These integratedcircuit structures can be used, for instance, to implementsystem-on-chip (SOC) devices, which may include an at least one of amicroprocessor, a microcontroller, memory, and a power managementcircuit, for example. In some embodiments, multiple functions can beintegrated into one or more chips (e.g., for instance, note that thecommunication chip 1006 can be part of or otherwise integrated into theprocessor 1004).

The communication chip 1006 enables wireless communications for thetransfer of data to and from the computing system 1000. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication chip 1006 may implementany of a number of wireless standards or protocols, including but notlimited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE,GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The computing system 1000 may include a plurality ofcommunication chips 1006. For instance, a first communication chip 1006may be dedicated to shorter range wireless communications such as NFC,Wi-Fi, and Bluetooth, and a second communication chip 1006 may bededicated to longer range wireless communications such as GPS, EDGE,GPRS, CDMA, WiMAX, LTE, Ev-DO, and others.

The processor 1004 of the computing system 1000 includes an integratedcircuit die packaged within the processor 1004. In some embodiments, theintegrated circuit die of the processor includes onboard memorycircuitry that is implemented with one or more semiconductor ortransistor structures as variously described herein (e.g., wheremultiple fin dimensions are used on the single die to achieve finnedtransistor structures having varying channel dimensions). The term“processor” may refer to any device or portion of a device thatprocesses, for instance, electronic data from registers and/or memory totransform that electronic data into other electronic data that may bestored in registers and/or memory.

The communication chip 1006 may also include an integrated circuit diepackaged within the communication chip 1006. In accordance with somesuch example embodiments, the integrated circuit die of thecommunication chip includes one or more devices implemented with one ormore transistor structures as variously described herein (e.g., on-chipprocessor or memory). As will be appreciated in light of thisdisclosure, note that multi-standard wireless capability may beintegrated directly into the processor 1004 (e.g., where functionalityof any chips 1006 is integrated into processor 1004, rather than havingseparate communication chips). Further note that processor 1004 may be achip set having such wireless capability. In short, any number ofprocessor 1004 and/or communication chips 1006 can be used. Likewise,any one chip or chip set can have multiple functions integrated therein.

In various implementations, the computing system 1000 may be a laptop, anetbook, a notebook, a smartphone, a tablet, a personal digitalassistant (PDA), an ultra-mobile PC, a mobile phone, a desktop computer,a server, a printer, a scanner, a monitor, a set-top box, anentertainment control unit, a digital camera, a portable music player,or a digital video recorder. In further implementations, the system 1000may be any other electronic device that processes data or employs one ormore integrated circuit structures or devices as variously describedherein.

Further Example Embodiments

The following examples pertain to further embodiments, from whichnumerous permutations and configurations will be apparent.

Example 1 is an integrated circuit comprising: a first set of one ormore fins formed on and from a substrate, the first set of fins eachhaving source/drain regions and a channel region, wherein the first setof fins each have a first width (W1) in the source/drain regions and asecond width (W2) in the channel region, and wherein W2 is less than W1;and a second set of one or more fins formed on and from the substrate,the second set of fins each having source/drain regions and a channelregion, wherein the second set of fins each have a third width (W3) inthe source/drain regions and the channel region.

Example 2 includes the subject matter of Example 1, wherein: at leastone of the fins in the first or second sets has a first channel heightat a first location on the fin and a second channel height at a secondlocation on the fin; and/or at least one of the fins in the first sethas a first channel height and one of the fins in the second set has asecond channel height; wherein the first and second channel heightscomprise intentionally different channel heights.

Example 3 includes the subject matter of any of Examples 1-2, wherein W1is greater than 15 nm and W2 is 15 nm or less.

Example 4 includes the subject matter of any of Examples 1-3, wherein W1is between 2 nm and 6 nm greater than W2.

Example 5 includes the subject matter of any of Examples 1-4, wherein W2is at least 5 nm.

Example 6 includes the subject matter of any of Examples 1-5, wherein W3is substantially similar to W1.

Example 7 includes the subject matter of Example 6, whereinsubstantially similar means within 1 nm.

Example 8 includes the subject matter of any of Examples 1-7, whereinthe second set of fins have substantially different widths in thesource/drain regions as compared to the channel region.

Example 9 includes the subject matter of any of Examples 1-8, whereinthe first set of fins and the second set of fins each have at least onesemiconductor device built thereon.

Example 10 includes the subject matter of Example 9, wherein thesemiconductor devices are p-MOS, n-MOS, or CMOS transistor devices.

Example 11 includes the subject matter of any of Examples 1-10, furthercomprising a third set of fins formed on and from the substrate, thethird set of fins each having source/drain regions and a channel region,wherein the third set of fins each have a fourth width (W4) in thesource/drain regions and a fifth width (W5) in the channel region.

Example 12 includes the subject matter of Example 11, wherein W5 is notequal to W2.

Example 13 includes the subject matter of any of Examples 1-12, whereinthe integrated circuit is a system-on-chip (SOC) device.

Example 14 includes a mobile computing system comprising the subjectmatter of any of Examples 1-13.

Example 15 is a method of forming an integrated circuit, the methodcomprising: performing a trench etch to form fins and trenches in asubstrate, wherein each fin has a first width (W1); depositing aninsulator material in the trenches; forming dummy gates on channelregions of the fins; depositing an additional insulator layer overtopography of the fins and dummy gates; lithographically defining afirst area to be opened; removing the dummy gate in the first area tore-expose the channel region of the fins in the first area; andperforming a first trim etch on the channel region of the fins in thefirst area, wherein the trimmed channel region of each fin in the firstarea has a second width (W2), and wherein W2 is less than W1.

Example 16 includes the subject matter of Example 15, further comprisingrepeating the processes of lithographically defining an area to beopened, removing the dummy gate in that area to re-expose the channelregion of the fins in that area, and performing a trim etch on thechannel region of the fins in that area to achieve fins having channelregions of varying dimensions.

Example 17 includes the subject matter of any of Examples 15-16, furthercomprising: removing the dummy gate in the second area to re-expose thechannel region of the fins in the second area; and performing a secondtrim etch on the channel region of the fins in the second area, whereinthe trimmed channel region of each fin in the second area has a thirdwidth (W3), and wherein W3 is less than W1.

Example 18 includes the subject matter of any of Examples 15-17, whereinlithographically defining comprises forming a hardmask layer andpatterning the area to be opened.

Example 19 includes the subject matter of any of Examples 15-18, whereinperforming a trim etch comprises at least one of low ion energy plasmaprocessing using chlorine based chemistry and thermal processing. 2

Example 20 includes the subject matter of any of Examples 15-19, whereinperforming a trim etch comprises using chlorine based chemistry andusing less than 5 kW of radio frequency energy for between 10 and 40seconds.

Example 21 includes the subject matter of any of Examples 15-20, whereinperforming a trim etch comprises using chlorine based chemistry andusing less than 1 kW of radio frequency energy for between 10 and 40seconds.

Example 22 includes the subject matter of any of Examples 15-19, whereinperforming a trim etch comprises using thermal processing and using lessthan 900 degrees C. heat in an epitaxial reactor for between 20 and 120seconds in the presence of HCl.

Example 23 includes the subject matter of any of Examples 15-19, whereinperforming a trim etch comprises using thermal processing and using lessthan 700 degrees C. heat in an epitaxial reactor for between 20 and 120seconds in the presence of Cl₂.

Example 24 includes the subject matter of any of Examples 15-23, whereinthe substrate material comprises silicon (Si).

Example 25 includes the subject matter of any of Examples 15-24, whereinW1 is greater than 15 nm and W2 is 15 nm or less.

Example 26 includes the subject matter of any of Examples 15-25, whereinW1 is between 2 nm and 6 nm greater than W2.

Example 27 includes the subject matter of any of Examples 15-26, whereinW1 is greater than 10 nm.

Example 28 includes the subject matter of any of Examples 15-27, whereinW2 is at least 5 nm.

Example 29 includes the subject matter of any of Examples 17-28, whereinW3 not equal to W2.

Example 30 includes the subject matter of any of Examples 17-29, furthercomprising forming at least one semiconductor device on fins in thefirst area, fins in the second area, and/or fins not in the first orsecond areas.

Example 31 includes the subject matter of Example 30, wherein the one ormore semiconductor devices are p-MOS, n-MOS, or CMOS transistor devices.

Example 32 includes an apparatus comprising means for performing thesubject matter of any of Examples 15-29.

Example 33 includes an integrated circuit comprising: a first set of oneor more transistors including finned channel regions formed on and froma substrate; and a second set of one or more transistors includingfinned channel regions formed on and from the substrate; wherein, aboveisolation regions, at least one of the height and width dimensions ofthe first set of channel regions is different than the correspondingdimension of the second set of channel regions.

Example 34 includes the subject matter of Example 33, wherein the firstset of channel regions has a first width (W1) within isolation regionsand a second width (W2) above the isolation regions, and W2 is less thanW1.

Example 35 includes the subject matter of Example 34, wherein W1 isgreater than 15 nm and W2 is 15 nm or less.

Example 36 includes the subject matter of any of Examples 34-35, whereinW1 is between 2 nm and 6 nm greater than W2.

Example 37 includes the subject matter of any of Examples 33-36,wherein, above isolation regions, the width of the first set of channelregions is less than the width of the second set of channel regions.

Example 38 includes the subject matter of any of Examples 33-36,wherein, above isolation regions, the height of the first set of channelregions is less than the width of the second set of channel regions.

Example 39 includes the subject matter of any of Examples 33-36,wherein, above isolation regions, the width and height of the first setof channel regions is less than the width and height, respectively, ofthe second set of channel regions.

Example 40 includes the subject matter of any of Examples 33-39, whereinthe transistors are p-MOS, n-MOS, and/or CMOS transistors.

Example 41 includes a system-on-chip (SOC) device comprising the subjectmatter of any of Examples 33-40.

Example 42 includes the subject matter of Example 41, further comprisingat least one of a microprocessor, a microcontroller, memory, and a powermanagement circuit.

The foregoing description of example embodiments has been presented forthe purposes of illustration and description. It is not intended to beexhaustive or to limit the present disclosure to the precise formsdisclosed. Many modifications and variations are possible in light ofthis disclosure. It is intended that the scope of the present disclosurebe limited not by this detailed description, but rather by the claimsappended hereto. Future filed applications claiming priority to thisapplication may claim the disclosed subject matter in a differentmanner, and may generally include any set of one or more limitations asvariously disclosed or otherwise demonstrated herein.

1. An integrated circuit comprising: a first set of fins formed on andfrom a substrate, the first set of fins each having source/drain regionsand a channel region, wherein the first set of fins each have a firstwidth (W1) in the source/drain regions and a second width (W2) in thechannel region, and wherein W2 is less than W1; and a second set of finsformed on and from the substrate, the second set of fins each havingsource/drain regions and a channel region, wherein the second set offins each have a third width (W3) in the source/drain regions and thechannel region.
 2. The integrated circuit of claim 1, wherein: at leastone of the fins in the first or second sets has a first channel heightat a first location on the fin and a second channel height at a secondlocation on the fin; and/or at least one of the fins in the first sethas a first channel height and one of the fins in the second set has asecond channel height; wherein the first and second channel heightscomprise intentionally different channel heights.
 3. The integratedcircuit of claim 1, wherein W1 is greater than 15 nm and W2 is 15 nm orless.
 4. The integrated circuit of claim 1, wherein W1 is between 2 nmand 6 nm greater than W2.
 5. The integrated circuit of claim 1, whereinW3 is substantially similar to W1.
 6. The integrated circuit of claim 1,wherein the first set of fins and the second set of fins each have atleast one semiconductor device built thereon.
 7. The integrated circuitof claim 6, wherein the semiconductor devices are p-MOS, n-MOS, or CMOStransistor devices.
 8. The integrated circuit of claim 1, furthercomprising a third set of fins formed on and from the substrate, thethird set of fins each having source/drain regions and a channel region,wherein the third set of fins each have as fourth width (W4) in thesource/drain regions and a fifth width (W5) in the channel region. 9.The integrated circuit of claim 1, wherein W5 is not equal to W2. 10.The integrated circuit of claim 1, wherein the integrated circuit is asystem-on-chip (SOC) device.
 11. A method of fanning an integratedcircuit, the method comprising: performing a trench etch to form finsand trenches in a substrate, wherein each fin has a first width (W1);depositing an insulator material in the trenches; forming dummy gates onchannel regions of the fins; depositing an additional insulator layerover topography of the fins and dummy gates; lithographically defining afirst area to be opened; removing the dummy gate in the first area tore-expose the channel region of the fins in the first area; andperforming a first trim etch on the channel region of the fins in thefirst area, wherein the trimmed channel region of each fin in the firstarea has a second width (W2), and wherein W2 is less than W1.
 12. Themethod of claim 11, further comprising repeating the processes oflithographically defining an area to be opened, removing the dummy gatein that area to re-expose the channel region of the fins in that area,and performing a trim etch on the channel region of the fins in thatarea to achieve fins having channel regions of varying dimensions. 13.The method of claim 11, further comprising: lithographically defining asecond area to be opened; removing the dummy gate in the second area tore-expose the channel region of the fins in the second area; andperforming a second trim etch on the channel region of the fins in thesecond area, wherein the trimmed channel region of each fin in thesecond area has a third width (W3), and wherein W3 is less than W1. 14.The method of claim 11, wherein lithographically defining comprisesforming a hardmask layer and patterning the area to be opened.
 15. Themethod of claim 11, wherein performing a trim etch comprises at leastone of low ion energy plasma processing using chlorine based chemistryand thermal processing.
 16. The method of claim 11, wherein performing atrim etch comprises using chlorine based chemistry and using less than 5kW of radio frequency energy for between 10 and 40 seconds.
 17. Themethod of claim 11, wherein performing a trim etch comprises usingthermal processing and using less than 900 degrees C. heat in anepitaxial reactor for between 20 and 120 seconds in the presence of HCl.18. The method of claim 11, wherein performing a trim etch comprisesusing thermal processing and using less than 700 degrees C. heat in anepitaxial reactor for between 20 and 120 seconds in the presence of Cl₂.19. The method of claim 11, wherein W1 is greater than 15 nm and W2 is15 nm or less.
 20. The method of claim 11, wherein W3 is not equal toW2.
 21. An integrated circuit comprising: a first set of one or moretransistors including finned channel regions formed on and from asubstrate; and a second set of one or more transistors including finnedchannel regions formed on and from the substrate; wherein, aboveisolation regions, at least one of the height and width dimensions ofthe first set of channel regions is different than the correspondingdimension of the second set of channel regions.
 22. The integratedcircuit of claim 21, wherein the first set of channel regions has afirst width (W1) within isolation regions and a second width (W2) abovethe isolation regions, and W2 is less than W1.
 23. The integratedcircuit of claim 21, wherein, above isolation regions, the width of thefirst set of channel regions is less than the width of the second set ofchannel regions.
 24. The integrated circuit of claim 21, wherein, aboveisolation regions, the height of the first set of channel regions isless than the width of the second set of channel regions.
 25. Theintegrated circuit of claim 21, wherein, above isolation regions, thewidth and height of the first set of channel regions is less than thewidth and height, respectively, of the second set of channel regions.